title: Labdane diterpenoids from Leonurus sibiricus.
abstract: Six new labdane diterpenoids, preleosibirone A (1), 13-epi-preleosibirone A (2), isopreleosibirone A (3), leosibirone A (4), leosibirone B (5), and 15-epi-leosibirone B (6), were isolated from the leaves of Leonurus sibiricus. The absolute configurations of 1, 2, 5, and 6 were established by X-ray crystallographic analyses, and leosibirone A (4) was shown to be an artifact of the isolation process.
authors.affiliation: Department of Pharmacognosy, School of Pharmacy, University of Mississippi, University, Mississippi 38677-1848, USA.
authors.forename: Hankui
authors.initials: H
authors.lastname: Wu
authors.forename: Frank R
authors.initials: FR
authors.lastname: Fronczek
authors.forename: Daneel
authors.initials: D
authors.lastname: Ferreira
authors.forename: Charles L
authors.initials: CL
authors.lastname: Burandt
authors.forename: Jordan K
authors.initials: JK
authors.lastname: Zjawiony
mesh_terms: D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry* / Q000302:isolation & purification*; D031332:Leonurus / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry
chemical_list: D004224:Diterpenes; C433017:labdane